Paper Processing Composition and Process of Production

ABSTRACT

A process for improving the dry strength of the paper by applying a dry-strength enhancing composition to pulp during a paper-making process, said dry-strength enhancing composition comprising a solution comprising an acid mixed with at least one metal ion wherein the metal ion is generally provided as a metal sulfate or a solubilized sulfate to form a mixture (I), wherein the mixture generates an exothermic reaction to form a mixture (II) and wherein the mixture is cooled to form the dry-strength enhancing composition.

RELATED CASES

This application claims the priority of provisional application Ser. No. 62/616,080 filed Jan. 11, 2018, the complete content of which is hereby incorporated by reference.

FIELD OF INVENTION

The present invention is related to the papermaking arts. More specifically, the present invention relates to a process for improving the dry strength and barrier properties in paper and paper products.

BACKGROUND OF THE INVENTION

The invention relates to a process for making paper and a composition and method to increase the strength properties and improve the barrier properties of the paper.

There is an enormous demand to develop methods which prevent the deterioration of foodstuffs, both human and agricultural. One way to accomplish this is through the development of packaging with properties including robustness and strength, allowing it to be used in paper and paperboard manufacture and transformation. Currently, to increase paper strength, it is common practice to add cationic starch at the wet-end stage of the papermaking process. The wet-end of the papermaking process refers to the stages of the papermaking process, wherein a pulp of fibers obtained from cellulose-based materials, such as recycled, used paper, wood, cotton, or alternative sources, is being processed. The term “wet-end” refers to the high volume of water with which the pulp is mixed in the early stages of paper production.

Additionally, the barrier properties of paper-based products may be enhanced by a variety of compounds which are known in the art. It is well known in the art that various polysaccharide compositions have been used as additives in the production of paper and paper products. It is desirable to provide polysaccharide compositions that may be useful in the production of paper products that have oil and grease resistance. The resulting paper products having enhanced characteristics of oil and grease resistance have utility in many applications. Among those applications, the paper products could be useful in food packaging, oil and grease resistant food containers, and release paper for frozen foods.

Regarding barrier properties, companies are migrating away from existing barrier product technology, particularly perfluorochemicals (PFCs), due to both their biopersistence and their environmental persistence. PFC based products potentially leach chemicals into the environment while lacking the ability to be recycled and/or repulped. The same can be said for persistent organic pollutants (POPs) which are organic compounds that are resistant to environmental degradation through chemical, biological and photolytic processes. POPs are characterized by high molecular mass, low water solubility, semi-volatility, high lipid solubility, and stability. These traits allow for bioaccumulation in fatty tissues of living organisms and slow metabolism, which confers the compound's persistence and accumulation into chains. The use of traditional coatings also results in significant product limitations. Abstaining from these traditional coatings, the use of water-based emulsions in combination with natural co-binders has allowed for the development of a bio-based and biodegradable grease resistant paper which is recyclable and repulpable.

Regarding recycling, the papermaking industry often requires more starch in the paper in part due to the environmental demand to use recycled paper. As paper is recycled, the fibers of the paper tend to become shorter and weaker, the latter of which is due to reduced interactions among the fibers. As a result, increased amounts of starch are necessary in the wet-end of the papermaking process to produce a paper which is sufficiently strong. It has been found that after paper has been recycled a certain number of times, the loss of strength due to recycling cannot always be compensated by simply adding starch. Accordingly, recycling ultimately leads to paper having an inferior paper strength.

Less expensive methods of production are always a goal in the paper industry. This can be achieved by incorporating large amounts of an inexpensive filler into the paper. However, a larger filler content of the paper results in a decline of paper strength, which gives rise to a demand for the addition of increased amounts of starch in the wet-end. Therefore, it is desired to increase the strength of paper and paper products without the incorporation of additional starch.

Maintaining high levels of dry strength is a critical parameter for many papermakers. Obtaining high levels of dry strength may allow a papermaker to make high performance grades of paper where greater dry strength is required, use less or lower grade pulp furnish to achieve a given strength objective, increase productivity by reducing breaks on the machine, or refine less and thereby reduce energy costs. The productivity of a paper machine is frequently determined by the rate of water drainage from a slurry of paper fiber on a forming wire. Thus, chemistry that gives high levels of dry strength while increasing drainage on the machine is highly desirable. The enhanced grease resistance further adds to the value of both the paper and the process of its manufacture. Thus, there is clearly a need for both products and methods which enhance the strength and improve the barrier properties (i.e. grease resistance) of the paper.

SUMMARY OF THE INVENTION

A primary objective of this invention is to provide for improved dry strength in paper and paperboard products.

Another objective of this invention is to provide for improved barrier properties (i.e. grease resistance) to paper and paperboard products.

A composition of matter formed by the following described method has been found to be effective in achieving improved dry strength and in improving the barrier properties in paper and paper board products.

A process for improving the dry strength of the paper by applying a dry-strength enhancing composition to pulp during a paper-making process, said dry-strength enhancing composition comprising a solution comprising an acid mixed with at least one metal ion wherein the metal ion is generally provided as a metal sulfate or a solubilized sulfate to form a mixture (I), wherein the mixture generates an exothermic reaction to form a mixture (II) and wherein the mixture is cooled to form the dry-strength enhancing composition.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a paper making process.

FIG. 2 is an illustration of a paper making machine.

FIG. 3 is an illustration of a paper making machine.

FIG. 4 is an illustration of an embodiment of a composition blending system.

FIG. 5 is an illustration of an embodiment of a composition blending system.

FIG. 6 is an illustration of an embodiment of a cooling system and reaction vessel.

FIG. 7 is an illustration of an embodiment of a cooling system.

FIG. 8 is an illustration of an embodiment of a reaction vessel.

DETAILED DESCRIPTION

The present invention now will be described more fully hereinafter in the following detailed description of the invention, in which some, but not all embodiments of the invention are described. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well as the singular forms, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the invention and the claims.

Paper is generally a matted or felted sheet of fibers usually vegetable but sometimes mineral, animal, or synthetic formed on a screen from a water suspension. The term “paper” is specifically limited to lighter weight, thinner, more flexible sheets formed in this manner. Sheets that are 0.012 inch (0.3 millimeter) or more in thickness, including Bristol board, container board, boxboard, wallboard, and so forth, are classified as paperboard. Paper product refers to any material produced by pressing moist fibers (i.e. cellulose pulp) derived from plant materials. Paper products may include paper of any thickness or basis weight, corrugated board, paperboard, or any combination thereof. The paper coating composition may be applied to a product or paper product using any method known in the industry including, but not limited to, immersion, rolling, spraying, padding or a combination thereof).

Papermaking Materials

Vegetable fibers for the manufacture of paper are obtained from many materials, including woods (spruce, fir, pine, hemlock, birch, poplar, gum, and others), cotton and linen rags, cotton linters, bagasse, bamboo, manila rope, esparto, cereal straws, flax straw, bast fibers from mulberry bark and mitsumata, and wastepaper. Mineral and synthetic papermaking materials include gypsum, asbestos, glass fiber, and synthetic polymers.

From the invention of paper until the middle of the 19th century, rags and linen were the chief materials from which paper was made. Rags (including cotton and linen threads, flax and hemp, raw cotton, and cotton linters) are still used in the manufacture of high-grade papers for (1) banknote and security papers, (2) legal documents for permanent records, (3) certain technical papers, including filter, tracing, and reproduction papers, (4) lightweight special papers for Bibles and cigarettes, and (5) high-grade stationery and letterheads. Rag papers may vary in rag content from 100% to 25%, the rest being wood pulp. The lower the rag content of a paper, the less it resembles an all-rag paper. Not until 1851 did the science of chemistry give the paper industry a process for turning trees into paper through the manufacture of pulp from wood. By the mid-20th century, however, over 90% of all papermaking fibers were derived from wood pulp.

Pulp Preparation

The pulp used in the instant invention may be prepared by any method known in the art. The main objective of the pulping process is the separation of the wood into its individual fibers of cellulose. The fibers are 0.12 to 0.2 inches (3-5 millimeters) long in the case of softwoods and slightly over 0.04 inch (1 millimeter) long in hardwoods; they are 0.0008 to 0.0012 inch (0.02-0.03 millimeter) in diameter. Wood contains about 50% cellulose, 30% lignin (which binds the fibers together), and 20% hemicellulose, resin, and fats. To convert wood to pulp, any of a variety of processes may be used, ranging from fully mechanical to fully chemical systems.

Prior to the pulping process, bark (which is not suited for papermaking) must be removed from the logs. The logs are conveyed for this purpose into huge, horizontal drums that rotate to remove the bark by mechanical abrasion. Other mechanical bark-removing devices include impact, chain, and scraper machines; bark may also be removed by chemical or hydraulic methods. In modern mills the bark is burned in combination fuel boilers to produce process steam or electricity.

The debarked logs are fed to a chipper, a huge rotating disk carrying 10 to 15 knives. The chips are screened to remove oversized and undersized chips, and the acceptable chips are conveyed to the pulp mill.

Mechanical Pulp

Stone groundwood pulp is made by grinding logs or blocks (bolts) of wood against a revolving abrasive stone in the presence of water. The logs are debarked but not chipped, fed to the grinder, and forced against the revolving stone by mechanical means.

Chip groundwood, or refiner mechanical pulp, is produced by feeding chips or sawdust between a set of rotating, ridged plates (or disks) of a disk refiner. An extension of the chip groundwood process is the thermomechanical process in which steam softens the chips prior to reduction in pressurized disk refiners.

Mechanical pulp is practically identical in composition with wood. The mechanical process is usually restricted to the spruces and firs and some of the softer hardwoods. Pulp yield is very high, amounting to nearly 90% of the dry-weight basis of the wood processed. Fresh mechanical pulp is light yellow in color. It is often bleached for the production of papers in which yellow would be undesirable. Its greatest use is for newsprint, magazine papers, certain packaging papers and board, and absorbent papers.

Several chemi-mechanical processes have been developed, in which the chips or bolts may be pretreated with sodium sulfite or caustic soda, so that grinding or refining consumes less power, generates less heat, and widens the range of wood species, including the hardwoods, that may be mechanically pulped. Pulp yields for these types of processes are between 80% and 90%.

Steam defibrated and exploded pulps are specially processed mechanical pulps used primarily in hardboard and other building papers.

Semichemical Pulp

The wood chips for semichemical pulp undergo a relatively mild chemical treatment prior to mechanical defibration in a disk refiner. The chemical treatment usually consists of sodium sulfite solution buffered with sodium carbonate or bicarbonate, or is a kraft green liquor (a solution containing soda ash and sodium sulfide). Some semichemical mills have switched to the “no-sulfur” process, in which soda ash alone or in combination with caustic soda is used as the cooking liquor. The semichemical process lends itself well to hardwoods, and pulp yields are in the range of 70% to 80%. The pulp is used most often in the manufacture of corrugated medium (the fluted portion of corrugated board).

Chemical Pulp

The chemical pulping processes are either acid (sulfite) or alkaline (soda and kraft) in nature, and the object of the cooking-liquor solution is to dissolve the non-cellulose components of the wood, especially the lignins, leaving the residual cellulose. Chips are “cooked” in the liquor under high temperatures and pressures in large retorts, called digesters, either in batches or continuously.

Straw, esparto, bamboo, cotton linters, bagasse, and other natural fibrous materials are converted into paper pulps by means of modified versions of the processes used with pulpwoods. For rags, rope, jute, and wastepaper, chemical treatment is largely limited to cleaning and purifying the stock in preparation for mechanical pulping.

De-inking, the process of removing ink and coatings from recycled wastepapers, is usually accomplished with caustic soda in combination with soda ash, sodium silicate, peroxide (for whitening), and other chemicals. De-inked and repulped wastepaper is an important supplementary source of pulp.

Bleaching

To produce white fibers from the brown or pale-yellow pulps, treatment with a bleaching agent is required. The nature of the bleaching operation depends on several factors: the type of raw material used to make the pulp, the pulping process, the degree of whiteness desired, and the purpose for which the pulp is to be used. Bleaching carries further the fiber purification accomplished in the pulping process. In the case of wood pulp, traces of lignin and other colored substances are removed or converted to colorless forms by bleaching. Most bleaching processes use an oxidizing agent (chlorine, a hypochlorite, chlorine dioxide, or hydrogen peroxide). For some pulps, especially groundwood, a strong reducing agent such as sodium hydrosulfite, or a strong oxidizing agent such as hydrogen peroxide, or both in sequence, have been found effective in whitening the pulp. A newer development is the use of oxygen as a partial replacement of chlorine in the first stage. The result is a reduction in the use of chlorine and water, and reduced effluents.

Bleaching of wood pulp usually is carried out in stages (from three to six or seven separate operations) in order to control the process and particularly in order to limit damage to the cellulose fiber, since paper made from overbleached pulp does not have full strength.

Stock Preparation

After the pulp fibers have been thoroughly washed to remove chemicals and impurities, they are given a mechanical treatment termed stock preparation (or beating and refining). Fibers that have been abraded and fibrillated by the knife edges or bars in the beater or refiner make stronger and denser papers than do the unrefined fibers. At this stage, rosin and alum are added to size the paper, thereby increasing its water resistance and rendering it suitable for pen-and-ink writing; and pigments and dyes are added to pulps from which colored papers will be made. To produce papers with special properties, wax emulsions, fillers (including clay and titanium dioxide), and other materials may be added during beating. Subsequently the mixture of fiber and water may be fed to a Jordan refiner, in which a shearing action cuts the fibers to shorter lengths.

Paper Machine

In the fourdrinier paper machine, the fiber/water mixture, containing more than 99% water, flows through a headbox to a finely woven endless wire-screen belt, which runs at speeds ranging from 300 to 3,000 feet (90-900 meters) per minute, and even faster in some instances. As it travels, the screen is given a horizontal shake to facilitate the formation of the wet web of paper, and water is drained through the screen, leaving the fibers on top. Suction boxes beneath the screen increase the rate of drainage. The newly formed web of paper is carried by an endless belt to press rolls, which remove more water and smooth the paper. Finally, to complete the papermaking operation, the paper is conveyed over a series of steam-heated rotating drums (driers) to be dried to a predetermined moisture content. To obtain a smooth surface finish, the paper may be passed through a calender stack at the dry end of the paper machine. A few examples of the overall process are shown illustrated in FIGS. 1, 2 and 3.

The most radical departure from the conventional fourdrinier design is the development of the twin-wire former. In twin-wire formers, the sheet is produced between two wire belts arranged in a more or less vertical orientation. Water is drained from the sheet in both directions, resulting in more rapid, controlled drainage and improved uniformity on both sides of the sheet. Twin-wire formers also operate at higher speeds and take up considerably less space than the horizontal fourdrinier table.

In the cylinder machine, the web of paper is formed on a cylindrical drum whose outer wall is a screen. The cylindrical screen mold is partially immersed in a vat of dilute pulp stock. As the stock water flows through the screen, its pulp content is deposited on the screen to make a web of paper. The cylinder is evacuated continually to maintain the flow of stock water through the screen. As the newly formed web is rotated out of the stock, it is picked up by an endless belt of felt and carried on for further treatment. Frequently batteries of cylinder machines are employed, and as the felt passes over each successive machine a new layer of paper is added. Cylinder machines are particularly suited for manufacturing multilayer sheets of paper whose outer layers are constituted of pulps differing in kind or color from the pulp used to make the inner layers.

When it leaves the paper machine, the paper, sometimes over 20 feet (6 meters) wide, is ready to be cut to size and finished for shipment. Finishing operations performed after the paper is wound on a large roll at the paper machine include slitting to form smaller rolls, rewinding, sheeting, trimming, sorting, counting, and packaging. Certain grades of paper are super-calendered to give them a high degree of smoothness. Coating materials, which produce special surface characteristics, may be applied either during the finishing stage (conventional coating) or while the paper is still on the paper machine (machine coating).

The instant invention includes a composition of matter which enhances the dry-strength of paper products.

In one embodiment, the dry-strength enhancing composition is a solution comprising an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof, mixed with at least one metal ion selected from zinc, magnesium, manganese, nickel, and iron, wherein the metal ion is generally provided as a metal sulfate or a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate to form a mixture (I), wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II) and wherein the mixture is cooled using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition and wherein the dry-strength enhancing composition has a pH value of less than 6.5.

The first basic ingredient used is a strong, low pH acid such as, phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof. Preferably, the acid is a food grade acid. The acid is of at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.9% purity. The acid may also be between approximately 98% to approximately 99.9% purity. The acid is mixed with at least one metal ion selected from zinc, magnesium, manganese, nickel, and iron wherein the metal ion is generally provided as a metal sulfate or a solubilized sulfate solution.

The next basic ingredient used is water selected from the group comprising: distilled water, deionized water, purified water, filtered water, pharmaceutical grade water, medical grade water, reverse osmosis water, or a combination thereof. The water preferably has a mega Ohm count between 5-19. The water is combined with a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate to form a solubilized sulfate.

The acid and the solubilized sulfate are combined within a reaction vessel to form a mixture (I). The reaction vessel may be any vessel known in the art which can sustain the temperatures generated during the formation of the instant dry-strength enhancing composition. The interior of the reaction vessel is coated with an inert material such as Teflon®, Kynar®, PVC, CPVC, Viton® and stainless steel. The reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel. The reaction generated when the acid in the solubilized sulfate passed through the reaction vessel is an exothermic reaction which generates temperatures in the range of 200° F. to 800° F., 300° F. to 800° F., 400° F. to 700° F., 500° F. to 800° F., 600° F. to 800° F. A cooling jacket surrounds the reaction vessel in order to control the temperature as the reaction takes place and the dry-strength enhancing composition is formed. The dry-strength enhancing composition then leaves the reaction vessel and is carried to the cooling system where the temperature is further decreased. The coolant used in either the cooling jacket or the cooling system is an air coolant, a liquid coolant, a gas coolant, or a combination thereof. The liquid coolant is selected from the group including: water, ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol, poly glycol, betaine, or a combination thereof. The gas coolant is selected from the group including: inert gas, hydrogen, nitrogen, carbon dioxide, or a combination thereof.

The dry-strength enhancing composition is produced in a continuous process. The dry-strength enhancing composition has a pH value of less than 6, less than 5, less than 4, less than 3, or less than 2. The dry-strength enhancing composition is added to or applied to pulp during the paper-making process.

In another embodiment, the dry-strength enhancing composition is a solution comprising an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof, mixed with a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate to form a mixture (I), wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II) and wherein the mixture is cooled using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition and wherein the dry-strength enhancing composition has a pH value of less than 6.5.

The first basic ingredient used is a strong, low pH acid such as, phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof. Preferably, the acid is a food grade acid. The acid is of at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.9% purity. The acid may also be between approximately 98% to approximately 99.9% purity.

The next basic ingredient used is water selected from the group comprising: distilled water, deionized water, purified water, filtered water, pharmaceutical grade water, medical grade water, reverse osmosis water, or a combination thereof. The water preferably has a mega Ohm count between 5-19. The water is combined with a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate to form a solubilized sulfate.

The acid and the solubilized sulfate are combined within a reaction vessel to form a mixture (I). The reaction vessel may be any vessel known in the art which can sustain the temperatures generated during the formation of the instant dry-strength enhancing composition. The interior of the reaction vessel is coated with an inert material such as Teflon®, Kynar®, PVC, CPVC, Viton® or stainless steel. The reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel. The reaction generated when the acid in the solubilized sulfate passed through the reaction vessel is an exothermic reaction which generates temperatures in the range of 200° F. to 800° F., 300° F. to 800° F., 400° F. to 700° F., 500° F. to 800° F., 600° F. to 800° F. A cooling jacket surrounds the reaction vessel in order to control the temperature as the reaction takes place and the dry-strength enhancing composition is formed. The dry-strength enhancing composition then leaves the reaction vessel and is carried to the cooling system where the temperature is further decreased. The coolant used in either the cooling jacket or the cooling system is an air coolant, a liquid coolant, a gas coolant, or a combination thereof. The liquid coolant is selected from the group including: water, ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol, poly glycol, betaine, or a combination thereof. The gas coolant is selected from the group including: inert gas, hydrogen, nitrogen, carbon dioxide, or a combination thereof.

The dry-strength enhancing composition is produced in a continuous process. The dry-strength enhancing composition has a pH value of less than 6.6, less than 6.5, less than 6, less than 5, less than 4, less than 3, or less than 2. The dry-strength enhancing composition is added to or applied to pulp during the paper-making process.

Looking to the figures wherein like numbers indicate like items, one can see an acidic, dry-strength enhancing composition blending system 10, 110 which includes a solubilized sulfate tank 20, 120 connected to reaction vessel 40, 140 by a pipe 24, 124. The flow of solubilized sulfate is controlled by a first valve 22, 122 located at the input end 25, 125 of the pipe 24, 124 and a second valve 27, 127 located at the output end 26, 126 of the pipe 24, 124. The system 10, 110 further includes an acid tank 30, 130 used as a holding tank for the acid utilized in the process. The acid tank 30, 130 is connected to the reaction vessel 40, 140 by a pipe 34, 134. The flow of acid is controlled by a first valve 32, 132 located at the input end 35, 135 of the pipe 34, 134 and a second valve 37, 137 located at the output end 36, 136 of the pipe 34, 134. Extending upward from the reaction vessel 40, 140 is a vent line 45, 145 which includes a control valve 47, 147 and a check valve 46, 146.

In one embodiment of the instant invention, the acid is added to an injection port that is ¼″ to 2″ in size at a flowrate which is adjustable. The sulfonated solution (10-80% saturated) is added to another injection port that is ¼″ to 2″ in size at a flowrate which is adjustable. Both injection ports are secured to the in-line static mixer(s) located within the reaction vessel. The acid and the sulfonated solution will start the blending process inside of the piping system. The piping system will include in-line static mixers and pipping channels (1-2″) approximately 4-25 feet long. The blending portion of the piping will be covered with a cooling jacket/bath. When the dry-strength enhancing composition completes the blending process, it will continue to the cooling system. This will allow the dry-strength enhancing composition to cool down prior to going to a holding tank.

Looking to FIGS. 4, 5, 6 and 8, several embodiments of reaction vessels 40 are illustrated. Within the reaction vessel lies one or more in-line static mixers 44, 144, 244 through which the acid in the solubilized sulfate pass, are mixed thoroughly and react. Surrounding the static mixers is the fall cooling tower cell 50, 150, 250 which includes a chamber 255 and a plurality of baffles 254. Each reaction vessel 40 further includes an outer casing 41 which encases the cooling tower cell. A plurality of valves 42, 142, 242 are secured to the outer casing which control the flow of coolant both from a coolant reservoir 51, 151, 251 through output pipes 52, 152, 252, into the fall tower cooling cell and back to the coolant reservoir through input pipes 53, 153, 253. The coolant from the coolant reservoir 51, 151, 251 flows through the chamber 255 over the outer surface of the in-line static mixers 44, 144, 244 while being agitated by a plurality of baffles 254 to ensure optimal heat exchange between the coolant in the in-line static mixer. Looking to FIGS. 4 and 5, the input pipes 53 and the output pipes 52 are to be connected to a coolant reservoir 51 (connection not illustrated).

When the reaction of the acid in the solubilized sulfate is complete within the reaction vessel resulting in the dry-strength enhancing composition, the composition exits the reaction vessel through a pipe 58, 158, 258 travels to the cooling system 70, 170, 270. Flow through this pipe is controlled by a valve 59, 159, 259. FIGS. 6 and 7 provide detailed embodiments of a cooling system 70, 170, 270. The cooling system is a series of pipes which make up a product he diffusion pathway 275 which are surrounded by a coolant absorption pathway 282. The dry-strength enhancing composition enters the cooling system 70, 170, 270 through an input 272 and travels through the product heat diffusion pathway 275 where heat is extracted from the dry-strength enhancing composition. He is extracted from the dry-strength enhancing composition by coolant stored in a coolant tank 280 which travels through an output pipe 281, through the coolant absorption pathway 282 (where heat is extracted), and back to the coolant tank through an output pipe 283. Flow to and from the coolant tank is controlled by a pair of valves 257. The composition then leaves the cooling system through an output 274 to a discharge line 95, 195, 295 and into a holding tank 98, 198, 298. Flow from the output 274 to the discharge line 95, 195, 295 is controlled by one or more valves 297.

Looking back to FIGS. 4 and 5, there is illustrated a control console 65, 165 and a programmable logic controller (PLC) 60, 160 which are used to control the process and the valves associated with the production of the dry-strength enhancing composition.

The instant invention also includes a composition of matter which is prepared by the process of providing an acid selected from the group including phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof, providing a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate, combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I), wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II) and cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and further cooling the dry-strength enhancing composition within a cooling system until a desired temperature is achieved and wherein the dry-strength enhancing composition has a pH value of less than 6.5.

In another embodiment, the composition of matter is prepared by the process of providing an acid selected from the group including phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof, providing at least one metal ion selected from zinc, magnesium, manganese, nickel, and iron, wherein the metal ion is generally provided as a metal sulfate or a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate, combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I), wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II) and cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and further cooling the dry-strength enhancing composition within a cooling system until a desired temperature is achieved and wherein the dry-strength enhancing composition has a pH value of less than 6.5.

The basic ingredients are identical to those described above. The reaction vessel may be any vessel known in the art which can sustain the temperatures generated during the formation of the instant dry-strength enhancing composition. The interior of the reaction vessel is coated with an inert material such as Teflon®, Kynar®, PVC, CPVC, Viton® and stainless steel. The reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel. The reaction generated when the acid in the solubilized sulfate passed through the reaction vessel is an exothermic reaction which generates temperatures in the range of 200° F. to 800° F., 300° F. to 800° F., 400° F. to 700° F., 500° F. to 800° F., 600° F. to 800° F. A cooling jacket surrounds the reaction vessel in order to control the temperature as the reaction takes place and the dry-strength enhancing composition is formed. The dry-strength enhancing composition then leaves the reaction vessel and is carried to the cooling system where the temperature is further decreased. The coolant used in either the cooling jacket or the cooling system is an air coolant, a liquid coolant, a gas coolant, or a combination thereof. The liquid coolant is selected from the group including: water, ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol, poly glycol, betaine, or a combination thereof. The gas coolant is selected from the group including: inert gas, hydrogen, nitrogen, carbon dioxide, or a combination thereof.

The dry-strength enhancing composition is produced in a continuous process. The dry-strength enhancing composition has a pH value of less than 6, less than 5, less than 4, less than 3, or less than 2.

In yet another embodiment a composition of matter is prepared by the process of providing an acid selected from the group including phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof, providing a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate, combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I), wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II) and cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and further cooling the dry-strength enhancing composition within a cooling system until a desired temperature is achieved and wherein the dry-strength enhancing composition has a pH value of less than 6.5.

In another embodiment, the composition of matter is prepared by the process of providing an acid selected from the group including phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof, providing at least one metal ion selected from zinc, magnesium, manganese, nickel, and iron, wherein the metal ion is generally provided as a metal sulfate or a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, Ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, Barium Sulfate, Calcium Sulfate, Iron Sulfate, Potassium Sulfate, Nickel Sulfate, radium sulfate, Strontium Sulfate and dihyro-sulfate, combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I), wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II) and cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and further cooling the dry-strength enhancing composition within a cooling system until a desired temperature is achieved and wherein the dry-strength enhancing composition has a pH value of less than 6.5.

The basic ingredients are identical to those described above. The reaction vessel may be any vessel known in the art which can sustain the temperatures generated during the formation of the instant dry-strength enhancing composition. The interior of the reaction vessel is coated with an inert material such as Teflon®, Kynar®, PVC, CPVC, Viton® and stainless steel. The reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel. The reaction generated when the acid in the solubilized sulfate passed through the reaction vessel is an exothermic reaction which generates temperatures in the range of 200° F. to 800° F., 300° F. to 800° F., 400° F. to 700° F., 500° F. to 800° F., 600° F. to 800° F. A cooling jacket surrounds the reaction vessel in order to control the temperature as the reaction takes place and the dry-strength enhancing composition is formed. The dry-strength enhancing composition then leaves the reaction vessel and is carried to the cooling system where the temperature is further decreased. The coolant used in either the cooling jacket or the cooling system is an air coolant, a liquid coolant, a gas coolant, or a combination thereof. The liquid coolant is selected from the group including: water, ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol, poly glycol, betaine, or a combination thereof. The gas coolant is selected from the group including: inert gas, hydrogen, nitrogen, carbon dioxide, or a combination thereof.

The dry-strength enhancing composition is produced in a continuous process. The dry-strength enhancing composition has a pH value of less than 6, less than 5, less than 4, less than 3, or less than 2.

The instant invention also includes a method of producing a dry-strength enhancing composition comprising the steps of:

(a) providing an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof;

(b) providing a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate;

(c) combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I);

-   -   wherein the mixture generates an exothermic reaction, generating         temperatures in the range of 150° F. to 950° F. to form a         mixture (II); and

(d) cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition, wherein the dry-strength enhancing composition has a pH value of less than 6.5 and;

(e) applying the dry-strength enhancing composition to pulp during a paper-making process to enhance the dry strength of the paper.

The instant invention also includes a method of producing a dry-strength enhancing composition comprising the steps of:

(a) providing an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof;

(b) providing at least one metal ion selected from zinc, magnesium, manganese, nickel, and iron;

-   -   wherein the metal ion is generally provided as a metal sulfate         or a solubilized sulfate solution comprising water and a sulfate         selected from the group including sodium sulfate, ammonium         sulfate, magnesium sulfate, zinc sulfate, manganese sulfate,         barium sulfate, calcium sulfate, iron sulfate, potassium         sulfate, nickel sulfate, radium sulfate, strontium sulfate and         dihyro-sulfate;

(c) combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I);

-   -   wherein the mixture generates an exothermic reaction, generating         temperatures in the range of 150° F. to 950° F. to form a         mixture (II);

(d) cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and

-   -   wherein the dry-strength enhancing composition has a pH value of         less than 6.5; and

(e) applying the dry-strength enhancing composition to pulp during a paper-making process and to enhance the dry strength of the paper.

The above method wherein the reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel. In a preferred embodiment, the inline blending apparatus is a static inline mixer which continuously blends the acid and the solubilized sulfate (mixture (I)) as it passes through the reaction vessel.

The instant invention also includes another method of producing a dry-strength enhancing composition comprising the steps of:

(a) providing an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof;

(b) providing a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, Ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, Barium Sulfate, Calcium Sulfate, Iron Sulfate, Potassium Sulfate, Nickel Sulfate, radium sulfate, Strontium Sulfate and dihyro-sulfate;

(c) combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I);

-   -   wherein the mixture generates an exothermic reaction, generating         temperatures in the range of 150° F. to 950° F. to form a         mixture (II); and

(d) cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition, wherein the dry-strength enhancing composition has a pH value of less than 6.5 and;

(e) applying the dry-strength enhancing composition to pulp during a paper-making process to enhance the dry strength of the paper.

The instant invention also includes a method of producing a dry-strength enhancing composition comprising the steps of:

(a) providing an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof;

(b) providing at least one metal ion selected from zinc, magnesium, manganese, nickel, and iron;

-   -   wherein the metal ion is generally provided as a metal sulfate         or a solubilized sulfate solution comprising water and a sulfate         selected from the group including sodium sulfate, Ammonium         sulfate, magnesium sulfate, zinc sulfate, manganese sulfate,         Barium Sulfate, Calcium Sulfate, Iron Sulfate, Potassium         Sulfate, Nickel Sulfate, radium sulfate, Strontium Sulfate and         dihyro-sulfate;

(c) combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I);

-   -   wherein the mixture generates an exothermic reaction, generating         temperatures in the range of 150° F. to 950° F. to form a         mixture (II);

(d) cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and

-   -   wherein the dry-strength enhancing composition has a pH value of         less than 6.5; and

(e) applying the dry-strength enhancing composition to pulp during a paper-making process and to enhance the dry strength of the paper.

The above method wherein the reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel. In a preferred embodiment, the inline blending apparatus is a static inline mixer which continuously blends the acid and the solubilized sulfate (mixture (I)) as it passes through the reaction vessel.

The basic ingredients are identical to those described above. The reaction vessel may be any vessel known in the art which can sustain the temperatures generated during the formation of the instant dry-strength enhancing composition. The interior of the reaction vessel is coated with an inert material such as Teflon®, Kynar®, PVC, CPVC, Viton® and stainless steel. The reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel. The reaction generated when the acid in the solubilized sulfate passed through the reaction vessel is an exothermic reaction which generates temperatures in the range of 200° F. to 800° F., 300° F. to 800° F., 400° F. to 700° F., 500° F. to 800° F., 600° F. to 800° F. A cooling jacket surrounds the reaction vessel in order to control the temperature as the reaction takes place and the dry-strength enhancing composition is formed. The dry-strength enhancing composition then leaves the reaction vessel and is carried to the cooling system where the temperature is further decreased. The coolant used in either the cooling jacket or the cooling system is an air coolant, a liquid coolant, a gas coolant, or a combination thereof. The liquid coolant is selected from the group including: water, ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol, poly glycol, betaine, or a combination thereof. The gas coolant is selected from the group including: inert gas, hydrogen, nitrogen, carbon dioxide, or a combination thereof.

For use to enhance the dry strength of paper and paperboard products, the composition of matter is applied or added at various stages during the paper product-making process. The composition of matter may be applied or added a single time during the process or multiple times. The composition of matter may be added or applied by any means or process known in the art. The addition of the composition of matter may require buffering which can be accomplished with any buffering agent known in the art (i.e. NaOH).

The composition of matter allows for the same amount of starch to be used as is customary in the art. The composition of matter acts to thin the starch out to enhance the qualities bestowed on the paper product from the starch.

In one embodiment of the instant invention, the composition of matter is added while in the pulp stage of the paper product-making process, prior to rolling. The paper is then manufactured by any manner known in the art.

In another embodiment of the instant invention, the composition of matter is added to the paper product after the paper product has been pressed, but prior to drying (i.e. added during the starch line).

In another embodiment of the instant invention, the composition of matter acts as a nucleating agent for calcium which is added during the paper product-making process.

The resulting paper products may be used for the packaging of foodstuffs as they are food-safe.

The exact chemical formula for the resultant composition is not clearly known.

Any method described herein may incorporate any design element contained within this application and any other document/application incorporated by reference herein.

In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefit and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the invention and the claims.

The present invention may be embodied in other forms without departing from the spirit and the essential attributes thereof, and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention. The invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein. 

1. A dry-strength enhancing composition comprising: a solution comprising an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof, mixed with; at least one metal ion selected from zinc, magnesium, manganese, nickel, and iron; wherein the metal ion is generally provided as a metal sulfate or a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate to form a mixture (i); wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II); wherein the mixture (II) is cooled using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and wherein the dry-strength enhancing composition has a pH value of less than 6.5.
 2. The dry-strength enhancing composition of claim 1 wherein the acid is a food grade acid.
 3. The dry-strength enhancing composition of claim 1 wherein the acid is of at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% purity.
 4. The dry-strength enhancing composition of claim 1 wherein the water is selected from the group comprising: distilled water, deionized water, purified water, filtered water, pharmaceutical grade water, medical grade water, reverse osmosis water, or a combination thereof.
 5. The dry-strength enhancing composition of claim 4 wherein the water has a mega Ohm count between 5-19.
 6. The dry-strength enhancing composition of claim 1 wherein the mixture generates temperatures in the range of 200° F. to 800° F., 300° F. to 800° F., 400° F. to 700° F., 500° F. to 800° F., 600° F. to 800° F., or a combination thereof.
 7. The dry-strength enhancing composition of claim 1 wherein the composition is produced in a continuous process.
 8. A process for enhancing the dry strength of the paper by applying the dry-strength enhancing composition as defined in claim 1 to pulp during a paper-making process.
 9. A dry-strength enhancing composition produced by the process of: providing an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof; providing a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate; combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I); wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II); and cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and wherein the dry-strength enhancing composition has a pH value of less than 6.5.
 10. The dry-strength enhancing composition of claim 9 wherein the reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel.
 11. The dry-strength enhancing composition of claim 9 wherein the acid is a food grade acid.
 12. The dry-strength enhancing composition of claim 9 wherein the acid is of at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% purity.
 13. The dry-strength enhancing composition of claim 9 wherein the water is selected from the group comprising: distilled water, deionized water, purified water, filtered water, pharmaceutical grade water, medical grade water, reverse osmosis water, or a combination thereof.
 14. A process for improving the dry strength of the paper by applying the dry-strength enhancing composition as defined in claim 9 to pulp during a paper-making process.
 15. A method of producing a dry-strength enhancing composition comprising the steps of: providing an acid selected from the group including: phosphoric acid, fumaric acid, nitric acid, sulfurous acid, sulfonic acid, perchloric acid, acetic acid, sulfuric acid or a combination thereof; providing a solubilized sulfate solution comprising water and a sulfate selected from the group including sodium sulfate, ammonium sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, barium sulfate, calcium sulfate, iron sulfate, potassium sulfate, nickel sulfate, radium sulfate, strontium sulfate and dihyro-sulfate; combining the acid and the solubilized sulfate within a reaction vessel to form a mixture (I); wherein the mixture generates an exothermic reaction, generating temperatures in the range of 150° F. to 950° F. to form a mixture (II); and cooling mixture (II) within the reaction vessel using either an air coolant, a liquid coolant, a gas coolant, or a combination thereof to form the dry-strength enhancing composition; and wherein the dry-strength enhancing composition has a pH value of less than 6.5.
 16. The method of claim 15 wherein the reaction vessel is an inline blending apparatus to which no pressure is added as the acid and the solubilized sulfate (mixture (I)) passes through the reaction vessel.
 17. The method of claim 15 wherein the inline blending apparatus is a static inline mixer which continuously blends the acid and the solubilized sulfate (mixture (I)) as it passes through the reaction vessel.
 18. The method of claim 15 wherein the acid is a food grade acid.
 19. The dry-strength enhancing composition of claim 15 wherein the acid is of at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% purity.
 20. The method of claim 15 further comprising the step of: applying the dry-strength enhancing composition to pulp during a paper-making process to enhance the dry strength of the paper. 